A Russian diver entered the Kursk nuclear submarine for the first time Wednesday but failed to find any of the 118 sailors who died when the vessel sank in August, a top navy commander said.

Admiral Vyacheslav Popov, commander of Russia's Northern Fleet, said the diver had so far only probed five metres (15 feet) along the main passageway of the Kursk's eighth compartment, the ITAR-TASS news agency said.

The diver, who entered the Kursk at 4:00 pm (1200 GMT), was unable to proceed any further because his diving suit was too bulky and his way forward was blocked, said Popov.

He had failed to open the hatch connecting to the floor below because it had been shut tight from the opposite side, added the admiral.

The diver had managed to slightly prise open a communication hatch to the neighboring ninth compartment, but was unable to fully open it, Popov added.

Other divers had meanwhile opened a separate emergency hatch to the ninth compartment, he said.

Fleet spokesman Vladimir Navrotsky told Interfax that the doomed sailors might have fled to lower levels of the eighth compartment at the time of the catastrophe that struck the Kursk on August 12.

Alternatively, they could have fled to neighboring compartments.

Navrotsky said that a short air pipe had forced the diver to cut short his initial sortie into the Kursk and return to the surface.

A Northern Fleet officer who asked to remain anonymous told AFP earlier that the divers, working in poor visibility 108 meters (355 feet) below the surface of the Barents Sea, should find at least seven bodies in the eighth compartment.

Normally, an officer, two first mates, a second mate and three sailors would be stationed in the section. But another three submariners from the neighboring compartment might have taken refuge there as well, he added.

After cutting their way into the vessel, Russian and Norwegian divers spent the day preparing for the hazardous operation by covering the jagged metal inside the Kursk with protective rubber material to avoid puncturing their diving suits.

A remote-controlled camera also probed the eighth compartment of the ill-fated Kursk, which was sent plunging to the seabed by two onboard explosions with the loss of all 118 crew.

Three divers -- two Russians and a Norwegian -- inside their bell-shaped submersible at a time are descending to the wreck site out of a total team of 18.

Only the Russians are scheduled to go inside Kursk while the Norwegian diver is due to stay to monitor the work -- MOSCOW (AFP)